JP2009119719A - Optical print head and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical print head which can make a focus adjusting mechanism thin. <P>SOLUTION: The optical print head is equipped with an LED array 3, a lens array 6, and the focus adjusting mechanism 10 which carries out focusing by adjusting a position in a Z direction of the lens array 6. The focus adjusting mechanism 10 includes at least a movable member 11 set movably in the Z direction in a state of coupling with the lens array 6, and an adjustment pin 12 for adjusting a movement amount in the Z direction of the movable member 11. Moreover, the movable member 11 is constituted to have an inclined surface 11d slantly inclined to a predetermined surface 1a of a heat sink 1. The movable member 11 is moved in the Z direction when the adjustment pin 12 presses the inclined surface 11d of the movable member 11 in an X direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical print head and an image forming apparatus including the same.

  Conventionally, an optical print head capable of selectively emitting light from a plurality of light emitting units arranged in a line is known, and an image is used as an exposure unit for forming an electrostatic latent image on a photoreceptor. It is mounted on a forming apparatus (see, for example, Patent Document 1). Conventionally, an optical print head in which an LED (light emitting diode) functions as a light emitting unit in the above-described configuration is also known.

  FIG. 12 is a diagram schematically showing an example of the structure of a conventional optical print head. Referring to FIG. 12, as a conventional optical print head structure, a plurality of LED array chips 102 are mounted on a predetermined circuit board 101. Each of the plurality of LED array chips 102 includes a predetermined number of LEDs 102a arranged in a line.

  In the conventional optical print head shown in FIG. 12, the light L emitted from the LED array chip 102 becomes diffused light. Therefore, the lens array 103 for condensing the light and forming an image on the photoconductor 110. Is provided. The lens array 103 includes a plurality of lenses 103a arranged in a line, and is arranged at a predetermined interval from the LED array chip 102 in the Z direction.

In the conventional configuration described above, it is necessary to provide a focus adjustment mechanism unit for adjusting the position of the lens array 103 in the Z direction in order to suppress a decrease in print quality due to the shift of the focus position. Although not shown, the focus adjustment mechanism unit includes at least an adjustment member coupled to the lens array 103, and adjusts the position of the lens array 103 in the Z direction by moving the adjustment member in the Z direction. It is configured as follows.
JP 2007-7933 A

  In the conventional configuration described above, when the lens array 103 including a plurality of lenses 103a having a relatively short focal length is used, the height of the structure including the lens array 103 in the Z direction, the lens array 103, the photoconductor 110, and the like. The interval in the Z direction becomes smaller. In this case, it is necessary to reduce the height in the Z direction of the focus adjustment mechanism (not shown).

  However, the conventional focus adjustment mechanism (not shown) described above is configured to adjust the position of the lens array 103 in the Z direction by moving an adjustment member connected to the lens array 103 in the Z direction. Therefore, if the height in the Z direction is reduced, the adjustment width when adjusting the position of the lens array 103 in the Z direction is narrowed. That is, the conventional focus adjustment mechanism has a problem that it is difficult to reduce the thickness by reducing the height in the Z direction.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical print head capable of reducing the thickness of the focus adjustment mechanism and an image forming apparatus including the same. Is to provide.

  In order to achieve the above object, an optical print head according to a first aspect of the present invention is mounted on a predetermined surface of a base and includes a light emitting element array including a plurality of light emitting elements that generate light, and a light emitting element array. An imaging element that includes a plurality of imaging elements that are arranged at a predetermined interval in a first direction perpendicular to a predetermined surface of the table, and that focus light from the light emitting element array to form an image on an image carrier An array and a focus adjustment mechanism that is provided on a predetermined surface of the base and performs focusing by adjusting the position of the imaging element array in the first direction. The focus adjustment mechanism unit is a movable member that is connected to the imaging element array so as to be movable in the first direction, and an adjustment for adjusting the amount of movement of the movable member in the first direction. And the movable member has an inclined surface inclined obliquely with respect to the predetermined surface of the base, and the adjusting member causes the inclined surface of the movable member to be inclined with respect to the predetermined surface of the base. The movable member is moved in the first direction by being pressed in the second horizontal direction.

  In the optical print head according to the first aspect, the adjustment member is moved in the second direction to adjust the position of the imaging element array in the first direction by using the focus adjustment mechanism as described above. Can be performed. That is, the adjustment width when adjusting the position of the imaging element array in the first direction is determined by the movement width of the adjustment member in the second direction. Accordingly, when the height of the focus adjustment mechanism portion in the first direction is limited, even if the height of the focus adjustment mechanism portion in the first direction is reduced, the movement width of the adjustment member in the second direction is reduced. Is not affected, the adjustment width at the time of adjusting the position of the imaging element array in the first direction is not narrowed. As a result, the focus adjustment mechanism can be thinned without narrowing the adjustment width when adjusting the position of the imaging element array in the first direction.

  In the optical print head according to the first aspect, the inclined surface of the movable member is preferably a curved inclined surface. According to this structure, when the movable member is moved in the first direction by pressing the inclined surface of the movable member in the second direction with the adjusting member, the movable member is moved finely in the first direction. Can do. Thereby, the position of the imaging element array connected to the movable member in the first direction can be adjusted with high accuracy. Accordingly, even if the focal depths of the plurality of imaging elements included in the imaging element array are relatively shallow, it is possible to easily perform focusing.

  In the optical print head according to the first aspect, preferably, the focus adjustment mechanism unit further includes a base member fixed to the base, and the movable member is provided with a guide pin extending along the first direction. In addition, a guide hole into which a guide pin of the movable member is inserted is formed in the base member. If comprised in this way, even if the inclined surface of a movable member is pressed in the 2nd direction by the adjustment member by making the guide pin of a movable member inserted in the guide hole of a base member, it is movable. It is possible to suppress the member from moving in the second direction. Further, since the guide pin of the movable member is inserted into the guide hole of the base member, rattling of the movable member when the movable member is moved in the first direction is suppressed. Can be smoothly moved in the first direction.

  In the optical printhead according to the first aspect, the light emitting element may be a light emitting diode, and the light emitting element array may be a light emitting diode array including a plurality of light emitting diodes.

  An image forming apparatus according to a second aspect of the present invention is an image forming apparatus including the optical print head according to any one of claims 1 to 4. With this configuration, it is possible to easily obtain an image forming apparatus capable of reducing the thickness of the focus adjustment mechanism.

  As described above, according to the present invention, it is possible to easily obtain an optical print head capable of reducing the thickness of the focus adjustment mechanism and an image forming apparatus including the same.

  FIG. 1 is an overall perspective view of an optical print head according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line 100-100 in FIG. 3 is a plan view of an LED array (light emitting element array) of the optical print head according to the embodiment shown in FIG. 1, and FIG. 4 is a lens array of the optical print head according to the embodiment shown in FIG. It is a top view of an imaging element array. FIG. 5 is a diagram for explaining the function of the lens array (imaging element array) shown in FIG. 6 is a perspective view of the focus adjustment mechanism of the optical print head according to the embodiment shown in FIG. 1, and FIG. 7 is a cross-sectional view taken along line 200-200 in FIG. 8 and 9 are diagrams of the movable member included in the focus adjustment mechanism shown in FIG. 6, and FIGS. 10 and 11 are diagrams of the base member included in the focus adjustment mechanism shown in FIG. is there. First, the structure of the optical print head according to the present embodiment will be described with reference to FIGS. Note that the optical print head of this embodiment is used in an image forming apparatus such as an electrophotographic printer.

  As the structure of the optical print head of this embodiment, as shown in FIGS. 1 and 2, a multilayer wiring board 2 is attached to a heat sink 1, and an LED array 3 is mounted on the multilayer wiring board 2. The heat sink 1 is an example of the “base” of the present invention, and the LED array 3 is an example of the “light emitting element array” of the present invention.

  The heat sink 1 has a smooth predetermined surface 1a formed in a rectangular shape when seen in a plan view. The LED array 3 mounted on the multilayer wiring board 2 is mounted on a predetermined surface 1 a of the heat sink 1. Thereby, it is possible to easily dissipate heat generated in the LED array 3.

  In addition, a plurality of fin portions 1b are formed on a portion (lower portion) opposite to the predetermined surface 1a of the heat sink 1 so as to protrude downward. The plurality of fin portions 1b of the heat sink 1 are formed in an elongated shape extending along the X direction (longitudinal direction of the predetermined surface 1a of the heat sink 1) and the Y direction (predetermined surface of the heat sink 1) orthogonal to the X direction. 1a in the short direction of 1a) and arranged at a predetermined interval. By using the heat sink 1 provided with a plurality of such fin portions 1b, the heat dissipation characteristics can be further improved.

  Further, at both ends in the X direction of the heat sink 1, screw holes 1c for screwing the heat sink 1 to a housing (not shown) of the image forming apparatus are formed one by one. The optical print head is fixed to the housing of the image forming apparatus by screwing the heat sink 1 to the housing of the image forming apparatus.

  The multilayer wiring board 2 is formed in a rectangular shape in which the X direction is the longitudinal direction (Y direction is the short direction) when viewed in plan. The multilayer wiring board 2 is placed on a predetermined surface 1a of the heat sink 1 so that screw holes 1c formed at both ends of the heat sink 1 are exposed. The multilayer wiring board 2 is screwed to the heat sink 1 with screws 8.

  As shown in FIGS. 2 and 3, the LED array 3 mounted on the multilayer wiring board 2 includes a plurality of LED array chips 3a arranged in a line in the X direction, and the plurality of LED arrays. Each of the chips 3a includes a predetermined number of LEDs 3b that generate light. The predetermined number of LEDs 3b included in each LED array chip 3a is such that the light emitting direction (the direction in which light having the highest luminance is emitted) is the Z direction (the direction perpendicular to the predetermined surface 1a of the heat sink 1). While being adjusted, they are arranged in a line at a predetermined density (for example, 600 dpi (dot per inch)) in the X direction. A predetermined number of LEDs 3 b included in each LED array chip 3 a are driven by a driver IC 4 mounted on the multilayer wiring board 2. The LED 3b is an example of the “light emitting element” in the present invention.

  Further, as shown in FIGS. 1 and 2, a cover member 5 screwed to the heat sink 1 by a screw 8 together with the multilayer wiring board 2 is provided on a predetermined surface 1 a of the heat sink 1. The cover member 5 is formed in a rectangular shape so that the X direction is the longitudinal direction (Y direction is the short direction) when viewed in plan, and the length of the cover member 5 in the X direction is a multilayer wiring. It is smaller than the length of the substrate 2 in the X direction. The cover member 5 covers a portion other than both end portions in the X direction of the multilayer wiring board 2.

  Further, the cover member 5 is formed with a concave portion 5a having an opening end on the multilayer wiring board 2 side. The LED array 3 and the driver IC 4 mounted on the multilayer wiring board 2 are covered with the recess 5a of the cover member 5 so that the surrounding space is substantially blocked from the outside. Thereby, it can suppress that a foreign material penetrate | invades on the optical path of the emitted light from LED array 3 in the vicinity of LED array 3. FIG. In addition, although not shown in figure, the recessed part 5a of the cover member 5 is formed in the elongate shape extended in a X direction seeing planarly.

  In addition, a slit 5 b for taking out the emitted light from the LED array 3 is formed in a portion of the cover member 5 that overlaps the LED array 3 when seen in a plan view. The slit 5b of the cover member 5 is formed in an elongated shape extending in the X direction when seen in a plan view. The lens array 6 is fitted in the slit 5 b of the cover member 5 while being sandwiched by the lens holder 7. That is, the lens array 6 is arranged at a predetermined interval from the LED array 3 in the Z direction. The lens array 6 is an example of the “imaging element array” in the present invention.

  As shown in FIGS. 4 and 5, the lens array 6 is composed of a plurality of lenses 6a arranged in a line in the X direction, and the plurality of lenses 6a has an optical axis oriented in the Z direction. It has been adjusted. The plurality of lenses 6a are arranged at a predetermined interval from each other and are bonded to each other by an adhesive member 6b. The lens array 6 collects the light L from the LED array 3 and forms an image on the photoconductor (image carrier) 20. The lens 6a is a refractive index distribution type collecting optical fiber lens that can form an equal magnification image, and is an example of the “imaging element” in the present invention.

  Further, as shown in FIG. 1, a focus adjustment mechanism portion 10 that is screwed to the heat sink 1 with screws 8 together with the multilayer wiring board 2 is provided on a predetermined surface 1 a of the heat sink 1. The focus adjustment mechanism unit 10 has a function of performing focusing by adjusting the position of the lens array 6 in the Z direction, and is disposed one by one on both ends of the lens array 6 in the X direction. . The focus adjustment mechanism unit 10 according to the present embodiment is configured to be able to convert the movement in the horizontal direction (X direction) into the vertical direction (Z direction). The Z direction that is the vertical direction is an example of the “first direction” in the present invention, and the X direction that is the horizontal direction is an example of the “second direction” in the present invention. Below, the structure of the focus adjustment mechanism part 10 of this embodiment is demonstrated in detail.

  As shown in FIGS. 6 to 11, the focus adjustment mechanism unit 10 of the present embodiment includes a movable member 11 installed so as to be movable in the Z direction with the lens array 6 (see FIG. 1) connected thereto, It includes at least an adjustment pin 12 that adjusts the amount of movement of the movable member 11 in the Z direction. The adjustment pin 12 is an example of the “adjustment member” in the present invention.

  The movable member 11 has a connecting hole 11a formed at the base thereof. And the lens array 6 (refer FIG. 1) is connected with the movable member 11 via the pin (not shown) inserted in the connection hole 11a. The movable member 11 is provided with a guide pin 11b extending along the Z direction.

  The movable member 11 is provided with a recess 11c formed so that the X direction is the depth direction and the opening end is rectangular when viewed from the Z direction. The lower surface 11d of the plurality of inner surfaces of the concave portion 11c of the movable member 11 is a curved surface whose cross section is inclined obliquely with respect to the predetermined surface 1a (see FIG. 1) of the heat sink 1. Hereinafter, it is referred to as an inclined surface 11d).

  The adjustment pin 12 is formed in a columnar shape extending along the X direction and is movably installed in the X direction. One end of the adjustment pin 12 is housed in the recess 11c of the movable member 11 so that the inclined surface 11d of the movable member 11 can be pressed in the X direction. Further, the adjustment pin 12 is processed so that the tip thereof is a curved surface. For this reason, in a state where the tip of the adjustment pin 12 is housed in the recess 11 c of the movable member 11, the tip of the adjustment pin 12 makes point contact with the inclined surface 11 d of the movable member 11.

  In the present embodiment, the movable member 11 is attached to the base member 13 fixed to the heat sink 1 (see FIG. 1). Specifically, the base member 13 is formed with a fitting portion 13 a having a shape reflecting the outer shape of the movable member 11. The movable member 11 is fitted into the fitting portion 13 a of the base member 13. Further, a guide hole 13b penetrating in the Z direction is formed in the fitting portion 13a of the base member 13, and a guide pin 11b of the movable member 11 is inserted into the guide hole 13b of the base member 13. Thereby, the movement of the movable member 11 in the Z direction is guided by the guide hole 13 b of the base member 13. That is, the movable member 11 can move only in the Z direction.

  Further, a guide hole 13 c penetrating in the X direction is formed in the fitting portion 13 a of the base member 13, and the adjustment pin 12 is inserted into the guide hole 13 c of the base member 13. As a result, the movement of the adjustment pin 12 in the X direction is guided by the guide hole 13 c of the base member 13. A hexagon socket set screw 14 is screwed into the guide hole 13c of the base member 13 from the outside with the adjustment pin 12 inserted. For this reason, by screwing the hexagon socket set screw 14 into the guide hole 13c of the base member 13, the adjustment pin 12 inserted into the guide hole 13c of the base member 13 is moved in the X direction.

  A leaf spring 15 is provided between the movable member 11 and the base member 13 so as to bias the movable member 11 in the Z direction. By providing such a leaf spring 15, the movable member 11 is always biased in the Z direction, so that the movable member 11 can be prevented from rattling in the Z direction.

  In the focus adjusting mechanism 10 of the present embodiment described above, as shown in FIG. 7, when the hexagon socket set screw 14 is moved in the X1 direction, the hexagon socket set screw 14 is adjusted in accordance with the movement in the X1 direction. The pin 12 also moves in the X1 direction. Thereby, the inclined surface 11 d of the movable member 11 is pressed in the X1 direction by the tip of the adjustment pin 12. At this time, since the movable member 11 can move only in the Z direction, the movable member 11 moves in the Z1 direction against the urging force of the leaf spring 15. On the other hand, when the hexagon socket set screw 14 is moved in the X2 direction, the pressing of the adjustment pin 12 in the X1 direction against the movable member 11 is released, so that the movable member 11 biased by the leaf spring 15 becomes Z2. Move in the direction. Thus, in the focus adjustment mechanism unit 10 of the present embodiment, the movable member 11 can be moved in the Z direction by moving the adjustment pin 12 in the X direction. That is, by moving the adjustment pin 12 in the X direction, the position of the lens array 6 (see FIG. 1) connected to the movable member 11 can be adjusted.

  After focusing is performed by adjusting the position of the lens array 6 (see FIG. 1) in the Z direction, the movable member 11 to which the lens array 6 is connected is fixed, for example, by the movable member 11 and the base member. 13 is filled with a UV curable resin in the gap between the two and the UV curable resin is cured. Further, the movable member 11 may be fixed using a screw or the like.

  In the present embodiment, by using the focus adjustment mechanism 10 as described above, the adjustment of the position of the lens array 6 in the Z direction (vertical direction) is performed by moving the adjustment pin 12 in the X direction (horizontal direction). Can be done. In other words, the adjustment width when adjusting the position of the lens array 6 in the Z direction is determined by the movement width of the adjustment pin 12 in the X direction. Therefore, when the height of the focus adjustment mechanism unit 10 in the Z direction is limited, even if the height of the focus adjustment mechanism unit 10 in the Z direction is reduced, the movement width of the adjustment pin 12 in the X direction is affected. Therefore, the adjustment width when adjusting the position of the lens array 6 in the Z direction is not narrowed. As a result, the focus adjustment mechanism unit 10 can be thinned without narrowing the adjustment width when adjusting the position of the lens array 6 in the Z direction.

  In addition, the focus adjustment mechanism unit 10 of the present embodiment is composed of only six members (movable member 11, guide pin 11b, adjustment pin 12, base member 13, hexagon socket set screw 14 and leaf spring 15). , Its structure can be very simple.

  In the present embodiment, as described above, the inclined surface 11d of the movable member 11 is curved, and the movable member 11 is pressed in the X direction with the tip of the adjustment pin 12 by moving the inclined surface 11d of the movable member 11 in the X direction. When moving 11 in the Z direction, the movable member 11 can be moved finely in the Z direction. Thereby, the position of the lens array 6 connected to the movable member 11 can be adjusted with high accuracy in the Z direction. Therefore, even if the focal depths of the plurality of lenses 6a included in the lens array 6 are relatively shallow, it is possible to perform focusing easily.

  In this case, by processing the tip of the adjustment pin 12 to be a curved surface, the tip of the adjustment pin 12 comes into point contact with the inclined surface 11d of the movable member 11, so that the movable member 11 moves in the Z direction. The movement of can be stabilized.

  In the present embodiment, as described above, the guide pin 11b extending along the Z direction is provided in the movable member 11, and the guide hole 13b into which the guide pin 11b of the movable member 11 is inserted is formed in the base member 13. As a result, the guide pin 11b of the movable member 11 is inserted into the guide hole 13b of the base member 13, so that the inclined surface 11d of the movable member 11 is pressed in the X direction by the tip of the adjustment pin 12. In addition, the movable member 11 can be prevented from moving in the X direction. Furthermore, when the guide pin 11b of the movable member 11 is inserted into the guide hole 13b of the base member 13, rattling of the movable member 11 when the movable member 11 is moved in the Z direction is suppressed. Therefore, the movable member 11 can be smoothly moved in the Z direction.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above embodiment, an example in which the present invention is applied to an optical print head using LEDs has been described. However, the present invention is not limited to this, and an optical print head other than an optical print head using LEDs (for example, an organic print head) The present invention can also be applied to an optical print head using an EL).

  In the above embodiment, the adjustment pin is moved in the X direction using the hexagon socket set screw. However, the present invention is not limited to this, and the adjustment pin is moved in the X direction using a micro gauge. It may be. If comprised in this way, the adjustment precision at the time of adjusting the position of the Z direction of the lens array connected with the movable member can be made higher.

  Moreover, in the said embodiment, although the inclined surface of the movable member was made into the curved shape, this invention is not restricted to this, You may make the inclined surface of a movable member flat.

1 is an overall perspective view of an optical print head according to an embodiment of the present invention. It is sectional drawing along the 100-100 line of FIG. It is a top view of LED array (light emitting element array) of the optical print head by one Embodiment shown in FIG. FIG. 2 is a plan view of a lens array (imaging element array) of the optical print head according to the embodiment shown in FIG. 1. It is a figure for demonstrating the function of the lens array (imaging element array) shown in FIG. It is a perspective view of the focus adjustment mechanism part of the optical print head by one Embodiment shown in FIG. It is sectional drawing along the 200-200 line | wire of FIG. It is a perspective view of the movable member contained in the focus adjustment mechanism part shown in FIG. It is sectional drawing of the movable member contained in the focus adjustment mechanism part shown in FIG. FIG. 7 is a perspective view of a base member included in the focus adjustment mechanism shown in FIG. 6. It is sectional drawing of the base member contained in the focus adjustment mechanism part shown in FIG. It is the figure which showed simply an example of the structure of the conventional optical print head.

Explanation of symbols

1 Heat sink (base)
1a Predetermined surface 3 LED array (light emitting element array)
3b LED (light emitting element)
6 Lens array (imaging element array)
6a Lens (imaging element)
DESCRIPTION OF SYMBOLS 10 Focus adjustment mechanism part 11 Movable member 11b Guide pin 11d Inclined surface 12 Adjustment pin (adjustment member)
13 Base member 13b Guide hole 20 Photoconductor (image carrier)

Claims (5)

A light emitting device array mounted on a predetermined surface of the base and including a plurality of light emitting devices for generating light;
The light-emitting element array is disposed at a predetermined interval in a first direction perpendicular to a predetermined surface of the base, and the light from the light-emitting element array is condensed and formed on an image carrier. An imaging element array including a plurality of image elements;
A focus adjustment mechanism provided on a predetermined surface of the base and performing focusing by adjusting a position of the imaging element array in the first direction;
The focus adjustment mechanism adjusts a movable member installed to be movable in the first direction while being connected to the imaging element array, and an amount of movement of the movable member in the first direction. And the movable member is configured to have an inclined surface inclined obliquely with respect to a predetermined surface of the base,
The movable member is moved in the first direction by pressing the inclined surface of the movable member in a second direction horizontal to the predetermined surface of the base by the adjusting member. Optical print head.   The optical print head according to claim 1, wherein the inclined surface of the movable member is a curved inclined surface. The focus adjustment mechanism unit further includes a base member fixed to the base,
The movable member is provided with a guide pin extending along the first direction, and the base member is formed with a guide hole into which the guide pin of the movable member is inserted. The optical print head according to claim 1 or 2. The light emitting element is a light emitting diode,
The optical print head according to claim 1, wherein the light emitting element array is a light emitting diode array including a plurality of the light emitting diodes.   An image forming apparatus comprising the optical print head according to claim 1.

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